Magnetic deflector for electric arcs in lamps, searchlights, and the like



I. P. YORKE. MAGNETIC DEFLECTOR FOR ELECTRIC ARCS IN LAMPS, SEARCHLIGHTS, AND THE LIKE APPLICATION FILED JUNE 25, I9I8.

Patented Sept. 21, 1920.

, 3 SHEETSSHEET I- QWII;

J. .P. YORKE.

MAGNETIC DEFLECTOR FOR ELECTRIC ARCS IN LAMPS, SEARCHLIGHTS, AND THE LIKE.

APPLICATION FILED JUNE 25. 1918.

. 1 5 3 9 g Patented Sept. 21, 1920.

W %I V 3 SHEETS--SHEET 2.

J. P. YORKE.

MAGNETIC DEFLECTOR FOR ELECTRIC ARCS IN LAMPS, SEARCHUGHTS, AND THE LIKE.

APPLICATION FILED JUNE 25, 19M].

Patented Sept. 21, 1920.

3 SHEETSSHEET 3.

JOHN PALEY YORKE, OF WESTMINSTER, LONDON, ENGLAND.

MAGNETIC nnrnnc'ron non nnno'rnro ARCS IN LAMPS, snencnnrenrsnnn THE LIKE.

, Specification of Letters Patent. Patented Sept. 21, 1926.

Application filed. June 25, 1918. Serial No. 241,773,

T 0 all whom it may concern Be it known that 1, JOHN PALEY YORKE, a subject of the King of England, residing at 'Westminster, London, England, have invented certain newv and nseful Improvements in Magnetic Deflectors for Electric Arcs in Lamps, Searchlights, and the'like, of which the following is a specification.

This invention relates to improvements in magnetic deflectors for arcs in lamps, searchlights and the like, and it refers more particularly to an electromagnetic deflector or centralizer for use with an electric arc projection lamp, such as a searchlight, though it is to be understood that the invention is applicable to other forms of electric arc lamps; Magnetic and electromagnetic deflectors have been used to deflect an arc downward orsidewise with the object of overcoming the upward tendency of" convection currents, or of deflecting the flame away from some portion of the mechanism or from the mirror or lens.

For this purpose magnetic deflectors have been proposed consisting of a band or bar of iron placed around the carbon with the ends of the iron just above the arc. The iron becomes magnetized by induction as soon as current flows through the carbons, and the magnetic field'of the iron reacts with the magnetic fieldfof the arc tending to force the latter downward or toward'the base of the lamp.

This type of deflector acts in one direction only, that is perpendicular to the carbons at all angles at which the lamp may be used, but with the arc in any position other than the horizontal the effect of the convection currents is not'in a direct line with the correction effect of the deflector, and consequently with inclined arcs the one direction type of deflector is valueless, and even with a horizontal are it is practically impossibleto obtain stability. It is an object'of the present invention to overcome these difliculties and to provide an electromagnetic deflector or centralizer which will maintain a central arc whatever the position or elevation of the lamp.

According to the present invention a magneticarc deflectoror centralizer' for" an electric arc lamp, such'as a projection lamp, is characterized by two or more magnetic fields acting on the are from two or more directions around the arc.

The magnetic arc deflectorv or centralizer 1 according to the present invention may also be further characterized by the fields being placed obliquely to a vertical plane which would pass longitudinally through the are when the latter is horizontal.

Preferably the magnetic fields are produced by fourcurrent-carrying conductors arranged parallel to each other and the arc,

and disposed around the are, such conduc tors being preferably connected so as to form two flat current-carrying'coilsarranged one on each side of the arc opposlte to eachother and approximately parallel to onev another and the arc.

.The means .for producing the field or fields may be adjustable in position in.rela-. tion to the are for the purpose of rendering the eflect of-one or more fields stronger or weaker as desired. 7

One form of arc deflector or centralizer according to the present invention will-now be described with reference to the accom-v g Figure 1 shows a general view of asearchlight projector, from the back, the mirror panying drawings wherein being removed, with the arc deflector .or centralizer in position. p

Fig. 2 showsa side elevation of the arc deflector or centralizer, with the mechanism for varying the position of the conductors partly in section, e Fig. 3 shows an end elevation thereof, and

Fig. 4 shows a plan of the support for the conductors forming the deflector and the mechanism'for raising, lowering and moving sidewise the said support.

On aplatform A mounted on the base of the lamp B and between the carbon-holders O, carrying electrodes O, is carried a hori- The screw D is connected by a universal coupling D to a shaftand hand-wheell) arranged outside the lamp, and the shaft E is connected through a'universal coupling E to a similar shaft and hand wheel'-"1il zontal screw D and a horizontal shaft E. ,5

also arranged outside the lamp; The screw D engages with an internal screw in the base of the column F, whereby thelatter may be moved sidewise as desired. On the means of the key G which isadapted to slide along the keyway G inthe shaft The gear-wheel G engages with a second gear-wheel G journaled in the base of the column F.- The :geair-wheel(in is mounted at shaft E is mounted a gear-wheel G by the bottom of an elevating screw H,'which screw engages with the hollow screw-threaded pillar J which telescopes into the column F. The pillar J carries at the top a platform K from which also depends {a guide-rod L which moves in the slot L in the column F.

To the platform K is secured the metal frame M, preferably of copper, which is of parallelogram form with one diagonal vertical and the other diagonal horizontal. The frame M is provided at the corners with bosses M h M *M, which are drilled to receive the ends of the two U-shaped metal members N, preferably of copper. The U- shaped metal members N are secured one with its ends to the bosses M and M and the otl1en-with its ends to the bosses M and The ends of these members are screwthreaded and are secured by nuts N Each U-sha-ped member N is connected at one end to the metal of the frame M and at the other end is insulated therefrom by insulating bushes and washers, the bosses M and M being larger and being drilled to a larger diameter than the bosses M and M to allow the introduction of the insulating bushes.

The frame M is arranged in such position that the are between the carbons O is about midway along the space between the U shaped members N.

The four horizontal conductors which with the ends form the two U-shaped members N constitute the means for producing the magnetic fields to act on the arc. The four conductors are connected in series with each other and with the arc, a connection being made to the insulated end of one conductor by means of the nut N and the current flowing thence through that conductor and the second conductor forming with it the U-shaped piece, then to the frame and from the frame through the two conductors forming the second U-shaped member, and' away througha suitable connection attached by means of the nut N 7 Normally the conductors are arrangedso that one is vertical above and one vertical below the carbons, while the other two lie to the right and left of the carbons respec tively, and they are connected so that the current in the conductors above and below 7 the carbons flows in an opposite direction to the current in the arc, while the current in the side conductors flows in the same direction as the current in the arc.

A magnetic field is thus produced around each conductor, and the fields are such that there is a downward force on the are exerted by the conductor above the carbons and an upward force by the conductor below the carbons, the right and left hand conductors producing left and right hand pullin forces respectively. Thus the arc is acted upon by four sets of forces.

By operating the hand-wheel D the defiector or centralizer may be moved toward the left or the right as desired, and thus the forces acting on the are from the right and left hand conductors may be varied, and similarly by operating the hand-wheel E the centralizer may be raised or lowered and the forces acting in a vertical direction similarly varied, the conductors forming the deflector always remaining parallel to the axis of the arc. Thus the position of the arc in relation to the carbons may be readily controlled and the effect of any convection currents or variations due'to non-homogeneous carbons can be overcome at once, and a perfectly central are easily maintained.

The frame M is insulated from the platform K by insulating packing.

The distances of the conductors from the carbons depends upon the strength'of the current flowing in the arc and upon the type of crater required. Different sized supportingframes M may be employed for different current ranges.

l/Vith a magnetic deflector according to the present invention the arc may be kept central for any position of the lamp.-

The present invention is particularly ap plicable to cinematograph projection lamps and to all other direct current are lamps, and it may be usedwith arc lamps in which the negative carbon is inclined at an angle to the positive. In the latter case the four conductors are fixed. parallel to the desired path of the arc.

Though in the particular form of the invention described above straight copper conductors have been described for producing the magnetic fields, it is to be understood that electro-magnets' having iron cores may be employed if desired, and in certain cases bar or horse-shoe permanent magnets, though with the latter the necessary proX- imity to the arc would 'soon spoil their magnetic properties.

Further, it is to be understood that the coils need not always be arranged in positions described above, and that more than two coils may, if desired, be employed around the arc, without departing from this invention. I

It is to be understood that no claim is made to the case in which two conductors only are employed exerting forces on the are which are in the same direction as one another, as for example produced by the edges or sides of a single coil arranged with one side oredgeabove the arc and the other side or edge below the arc.

What ll claim as my invention and desire to secure by Letters Patent is 1. A magnetic arc deflector for an electric arc-lamp, comprising a plurality of magnetic field-producing means cooperating to in planes each containing two of the means situated on opposite sides of the arc.

3. An arc deflector for an electric arclamp, comprising four currentcarrying conductors all connected in series, said conductors being arranged parallel to each other and to the arc, and disposed around the arc; and means for adjusting at least one of said conductors in relation to the arc.

4. An arc deflector for an electric arclamp, comprising four current-carrying conductors arranged parallel to each other and to the arc, and connected to form two flat current-carrying coils arranged one on each side of the arc opposite to each other and approximately parallel to one another and to the arc, one conductor of one coil substantially above the are and one conductor of the other coil substantially below the are when thelatter is horizontal, both carrying current in a direction opposite to the current in the arc, and the other two conductors of the two coils disposed one on each side of the are carrying current in the same direction as the are.

5. An arc deflector for an electric arclamp, comprising the combination with four current-carrying conductors arranged parallel to each other and to the arc and disposed in pairs around the arc, of means for moving one conductor of one pair away from the arc and simultaneously moving the opposite conductor of the other pair toward the are.

6. An arc deflector for an electric arc lamp comprising the combination with a frame of parallelogram form of conducting material of two U-shaped conducting bars supported from their ends across opposite sides of the frame, and insulating means insulating one end of each U-shaped conductor from the frame.

7 An arc deflector for an electric arc lamp comprising the combination with "a conducting rame of parallelogram form of two U-shaped conducting bars supported from their ends across opposite sides of the frame, insulating means insulating one end of each U-shaped conductor from the frame and means for connecting a supply of electricity to the insulated ends of the two conductors.

i 8. An arc deflector for an electric arc lamp comprising the'combination with four current-carrying conductors arranged parallel to each other and to the arc and connected to form two flat current-carrying coils arranged one, on each side of the arc opposite to each other, approximately parallel to one another and the arc and placed obliquely to a vertical plane which would pass longitudinally through the are when the latter is horizontal, of means for moving the two coils vertically and horizontally toward or away from the arc.

9. An arc deflector for an electric arc lamp comprising in combination a frame of parallelogram form ofconducting m'ateriahtwo U-shaped conducting bars supported from their ends across opposite sides of the frame, insulating means insulating one end of each U-shaped conductor from the frame, and

means for moving the frame vertically and horizontally in a plane at right angles the arc.

In testimony whereof I aflix my signature JOHN PALEY YORKE. 

